An indispensable part of modern large-scale plant cultivation is chemical plant protection in which different parasites are prevented from destroying a significant part of the crop and reducing the crop, respectively.
In the past decades several plant protecting agents came into general use which protect the cultivated plants against weed. However, their use resulted in a modification of the weed flora on the one hand, on the other hand in developing resistance individual types of weeds and consequently it was necessary to search for further newer herbicides in order to enable agent rotation and to control the resisting weeds, respectively.
Subsequent to general use of the symmetrical triazines successfully used in the control of dicotyledonous weeds the weed flora shifted to the direction of the monocotyledonous plants and at the beginning of the sixties chloro-acet-anilide-derivatives were employed for protection against them (U.S. Pat. No. 2,863,752). However, the protection against all monocotyledonous weeds, particularly against the resisting Sorghum halepense, did not succeed with these compounds (Propachlor, Alachlor and so on).
In the second half of the sixties N,N-disubstituted thiocarbamic type herbicides (U.S. Pat. No. 2,913,327) began to be very much used because of their suitability for the control of several weeds resisting the chloro-acet-anilide-derivatives.
Their use, however, is accompanied by disadvantages because they harm most of the cultivated plants in a dose necessary for a safe weed control to a greater or lesser degree and cause deformed leaves and sprouts.
In order to eliminate this undesired phytotoxic effect combinations of the thiolcarbamates and compounds of so-called antidotal effect were elaborated.
To the thiolcarbamate herbicide some percents of a substance exerting an antidotal effect are admixed and thus the selectivity of the preparation is increased with an unchanged herbicidal effect (Hungarian Patent Specification No. 165,736). However, these substances exerting an antidotal effect do not ensure sufficient protection against the phytotoxic effect of the thiolcarbamates for all cultivated plants and for all types of the individual plants, respectively.
Japanese Patent Specification No. 53-148,530 discloses a thiocarbonyl-amino acid-derivative of a newer structure but these derivatives cannot be used as herbicides, they are suitable only for sterilization.
The glycinethiolcarbamate derivatives disclosed in Japanese Patent Specification No. 52-151,146 have a somewhat similar structure as the above derivatives but these preparations are used in rice cultivations, the phytotoxic effect exerted on other cultivated plant cultures, however, is not known.
All these facts make the research for further new plant protecting agents necessary by which the disadvantages of the agents already used could be eliminated and the agent rotation necessary for safe cultivation could be determined.